They are spelled exactly as they are in Hebrew, but may be
pronounced differently. Almost a fifth of Yiddish words are derived from Hebrew.
Many have to do with religion. Most words ending in E are feminine.

There are several excellent dictionaries on this topic. They
include: Verterbukh fun loshn-kodesh shtamike verter in yidish by Yitshok Niborski,
and it is published by the Medem Library in Paris. A Guide to the More Common
Hebraic Words in Yiddish by Steven A. Jacobson at the University of Fairbanks,
Alaska. Hebrew and Aramaic Words in the Yiddish Language: Their Phonetic Spelling
and Translation into English and Russian by Moishe Wolf of Portland, Oregon.
It may be out of print.